From what I see of the vacuum system that was added to Claudine's
piano, there is a very simple test.  The spiral hose could even be
causing the leak through the spirals.  Simply pull the hose off the
fitting on the pedal chest and cover the opening with duct tape.
Let's see how it pumps then.

If it still leaks, the first thing I'd do is have someone pump quietly
and get under the piano and listen for leaks at every one of those old
joints.  Can't do that with the vacuum box running.  It would be easier
if you had a stethoscope (without the end piece).  You can get one for
about $10 at the store or on e-bay.

Craig Smith